1. Field of the Invention
The present invention relates to a slide fastener characterized in a stopper portion thereof.
2. Description of the Related Art
The slide fastener comprises a pair of fastener tapes, a plurality of coupling elements mounted on mating side edges of the tapes so as to be coupled with and separated from each other, a slider having a function for coupling/separating the coupling elements and stopper portions for limiting an end of operation of the slider. As the fastener tape, in general, a woven tape obtained by woven warp yarns and weft yarns has been widely used. A warp knitted tape having a warp knit structure has been prevailing.
Conventionally, a metallic stopper device is generally used for the aforementioned stopper portion of a slide fastener. The stopper device has a pawl which is to be pierced into the fastener tape and which can be mounted to the tape by wrapping the elements while being pierced through the tape. However, there was such a risk that the pawl of the metallic stopper device can come into contact with and injure the skin or can come into contact with yarns to be pulled or cut off. Such risk was needed to be prevented. For that reason, the structure of a stopper device itself has been improved so as to prevent the above-described trouble. On the other hand, there has been a proposal to produce a stopper device made of synthetic resin material, as disclosed in, for example, Japanese Utility Model Application Publication No. 63-33529 and Japanese Utility Model Application Publication No. 5-31932. The Japanese Utility Model Application Publication No. 63-33529 relates to a bottom stopper device in which thermoplastic synthetic resin film is fused integrally with fastener elements at one side of the fastener elements. A skirt portion is provided continuously to a main body of the bottom stopper device. The skirt portion has an uneven face at a portion where the fastener tape is bonded to the synthetic resin film. The skirt portion has a high-density portion in which material of the synthetic resin film exists densely and a low-density portion in which material of the synthetic resin film exists coarsely.
Because the bonding faces of the fastener tape and the synthetic resin film at the skirt portion are formed uneven, the bonding area becomes larger so that the bonding strength can be higher than a case where the bonding face is flat. Further, because the fastener tape portion at the skirt portion is formed with the high-density portion in which the synthetic resin film exists densely and the low-density portion in which it exists coarsely, the bonding strength between the fastener tape and the synthetic resin film can be intensified by the high-density portion. Furthermore, flexibility at the skirt portion can be maintained by the low-density portion, so that the synthetic resin film is prevented from separating from the fastener tape. Further, the stopper portion can be prevented from being broken at the skirt portion.
On the other hand, the Japanese Utility Model Application Publication No. 5-31932 relates to a top stopper device made of thermoplastic synthetic resin and having a U-shaped section, which is attached to an end portion of each fastener element row mounted along each of opposing side edges of right and left fastener tapes. Through holes are formed on an inner side of each of the fastener element row of the fastener tape. An end portion of the top stopper device having a U-shaped section is extended so as to close the through hole. The end portion is then fused and integrated through the through holes. Thus, an inverted portion is formed so that it can swing with respect to the integrated portion in a sliding direction of a slider.
With such a structure, particularly the end portion of the top stopper device, with which a flange of the slider come into contact, is fused and integrated firmly through the through holes provided in the fastener tape. Further, part of fused resin penetrates into the fastener tape and hardens. At the same time, front and rear leg portions and the inverted portion of the top stopper device nip a core portion of the fastener tape. Thus, even when a strong impact is applied to the top stopper device due to the sliding operation of the slider, the top stopper device would not be removed or dropped, thereby ensuring its stabilized stop function for a long time.
Further, the inverted portion of the top stopper device is so constructed as to be capable of swinging in the sliding direction of the slider. Therefore, if a column of the slider comes into contact with the inverted portion, the inverted portion is deflected in an advancing direction of the slider. Then, the flange of the slider makes contact with an end portion of the top stopper device. Thus, impact applied to the leg portions of the top stopper device by the slider can be eased, thereby protecting the top stopper device from being damaged by such impact.
As already described above, recently there has been a rising tendency that a warp knitted tape is used for a fastener tape of a slide fastener particularly used in clothes, in order to prevent a finished product, to which a fastener tape is sewed, from being waved. Specifically, in a case where a woven fastener tape is sewed to a thin, flexible cloth or it is sewed to a cloth in a curved manner, the finished product is likely to be waved because the woven fastener tape has a fine woven structure in general, which is not extensible with high stiffness. Therefore such sewing of the slide fastener to clothes requires high skill and experience of sewing in order to prevent generation of such waving. On the other hand, a fastener tape composed of a warp knit structure is capable of being stretched/contracted to some extent due to its knit structure. Therefore, the configuration of the fastener tape can be deformed easily so as to conform with the cloth. Thus, in this case, even if the fastener tape is sewed to a thin cloth or in a curved manner, no waving is generated.
As described above, the slide fastener which is to be sewed to clothes is required to be safe first. Further, the slide fastener, particularly a fastener tape of the slide fastener, is required not to be conspicuous with respect to a product to which the slide fastener is sewed. Specifically, women""s clothes such as skirt or underwear have been strongly demanded not to have its slide fastener seen from outside. Thus, currently, the slide fastener is sewed to a cloth as close to fastener elements as possible so that the fastener tape can hardly be seen in appearance.
However, as shown in by FIGS. 1 to 3 of the above-mentioned Japanese Utility Model Application Publication No. 63-33529 or FIGS. 3 to 6 in the above-mentioned Japanese Utility Model Application Publication No. 5-31932, each fixing end portion of conventional top and bottom stopper devices is largely extended more inwardly of a fastener tape than end faces of connecting portions for connecting upper/lower leg portions of fastener elements. Consequently, when the slide fastener is sewed to a cloth, the sewing machine foot makes contact with the fixing end portions of the top/bottom stopper portions, so that the sewing machine foot is deflected in a width direction of the slide fastener thereby having the sewing line meander. Consequently, not only appearance of the finished product is damaged due to conspicuousness of the meandering of the sewing line but also in the case of a thin cloth, it gets tense at the meandering portion thereby further harming the appearance further.
As already described, a proper function of the top/bottom stopper devices is to restrict the top and bottom positions of the slider for opening/closing a slide fastener and to prevent the slider from slipping out. However, the existence of the top/bottom stopper devices must not harm the appearance of cloth on which the slide fastener is attached, as well.
Accordingly, the present invention has been achieved to solve these problems. Therefore, an object of the present invention is to provide a slide fastener in which its sewing line does not meander when the slide fastener is sewed to a cloth, the sewing line can be provided as close to fastener elements as possible, and top/bottom stopper portions can be mounted to a fastener tape firmly while the fastener""s proper function is not damaged.
The above-described object can be achieved effectively by the present invention.
According to the present invention, there is provided a slide fastener having a stopper portion made of thermoplastic synthetic resin material at an end portion of a fastener element row mounted along a side edge of a fastener tape made of fabric, wherein the fastener tape has a rough-pattern-structure region at least adjacent to a side of the fastener element row on an inner side of the fastener tape, and an end portion of the stopper portion on the inner side of the fastener tape is disposed in the rough-pattern-structure region and fused to a foundation structure of the fastener tape in the rough-pattern-structure region.
Usually, a side edge portion of the fabric-made fastener tape of a slide fastener serves as a fastener element mounting region and is constructed in higher density than the other part of the fastener tape such as a tape main body region. According to the present invention, the rough-pattern-structure region, which has a coarse density, is formed between the fastener element mounting region and the tape main body region, more specifically between front ends of element leg portions and the tape main body region. According to the present invention, the end portion of the stopper portion on the inner side of the fastener tape is limited up to the rough-pattern-structure region which is located near the front ends of the element leg portions, so that the dimension of the stopper portion in the tape width direction can be shorter than the conventional ones. At the same time, the stopper portion is placed on a stopper-portion-formation part of the fastener tape in a fused condition, and then, integrated with at least composition yarns of the foundation structure existing in the rough-pattern-structure region to be fused thereto. At this time, the fused resin of the stopper portion penetrates through gaps of the rough-pattern-structure region and is fused to the composition yarns in the same rough-pattern-structure region so that it is fixed firmly.
By restricting the dimension of the stopper portion in the tape width direction, the stopper portion can be smaller. Consequently, when the slide fastener is sewed to the fabric, the sewing machine foot does not come into contact with the stopper portion in the area in which the stopper portion exists, so that the sewing line does not meander locally. As a result, not only the mounting style of the slide fastener is stabilized, but also a product having an excellent appearance can be produced.
Further, according to the present invention, it is preferable that the fastener tape is composed of a warp knit structure and the rough-pattern-structure region is formed between a first wale on an end of the fastener element mounting region on an inner side of the fastener tape and a second wale adjacent to the first wale on the inner side of the tape.
As a knitting yarn to be used for the rough-pattern-structure region, there are, for example, weft in-laid yarn for connecting between wales, sinker loops of tricot knitting yarn, sinker loops of two needle stitch yarn. In the knit structure between the wales formed with such knitting yarns, there exist gaps larger than the ones formed in the wales, thereby ensuring molten resin to penetrate into the foundation structure.
Furthermore, according to the present invention, it is preferable that the fastener tape is composed of a woven structure and the rough-pattern-structure region is formed adjacent to a structure at an end of the element mounting region on an inner side of the fastener tape. This rough-pattern-structure region can be formed by setting for example, the warp-yarn density to be lower than the warp-yarn density in the fastener element mounting region and the tape main body region, thereby ensuring molten resin to penetrate into the foundation structure.
Still further, according to the present invention, it is preferable that fusion of the stopper portion to the foundation structure of the fastener tape in the rough-pattern-structure region is carried out by ultrasonic heating or high frequency heating. The ultrasonic heating and high-frequency heating are performed by self-generation heat. The heating location is concentrated on a contact face between the two members to be fused together. Thus, the physical property of the fused members does not change except in the fused portions thereof, so that the fused portions do not become brittle very much. Additionally, an exposed surfaces of the two members after being fused turns to be beautiful finished surfaces along the configuration of an anvil, which is an ultrasonic horn or high-frequency electrode. Furthermore, because the fusion of small-dimension members such as a stopper portion and a fastener tape, which are the objects of the present invention, is completed in a short time of 2 to 5 seconds, productivity can be enhanced remarkably.
Still further, according to the present invention, it is preferable that the stopper portion is formed by injection molding and fusion of the end portion of the stopper portion to the foundation structure of the fastener tape in the rough-pattern-structure region is executed at the time of the injection molding. In the case of the above-described ultrasonic heating or high-frequency heating, the stopper portion is formed by fusing and integrating a material for the stopper portion, which is formed of a film piece or a resin piece, to the formation place for the stopper portion. According to the present invention, when the fastener tape is inserted into a mold to form the stopper portion together with elements, the stopper portion is formed while limiting the dimension thereof in the tape width direction to be within rough-pattern-structure region as described above. Upon this formation, molding resin for forming a front end of the stopper portion penetrates into the rough-pattern-structure region, so that it is integrated with each composition yarn within the rough-pattern-structure region.
Still further, according to the present invention, it is preferable that the stopper portion is a bottom stopper portion and the bottom stopper portion has a swollen portion on substantially a center of a surface thereof extending across the fastener element row in the tape width direction. As described previously, extended portions of an ordinary bottom stopper portion, which is extended from its main body portion covering right and left fastener elements in the tape width direction and which are fixed to the fastener tape, are long and thick to some extent. For this reason, when a slide fastener is opened by sliding a slider downward, the slider flanges come into contact with the bottom stopper portion, so that the slider cannot slide any more.
However, if it is intended to form a conventional slide fastener with the bottom stopper portion having not only a small length in the tape width direction as in the present invention, but also a small thickness, the stopper portion is likely go into an element guide groove of the slider so that when its pull is pulled downward, the slider can escape from the fastener element rows. Thus, according to the present invention, a swollen portion extending across the fastener element rows in the tape width direction is formed substantially in the center of the surface of the bottom stopper portion. When the slider is slid downward in order to open the slide fastener, part of the bottom stopper portion is received in the element guide groove of the slider. At this time, the swollen portion comes into contact with at least rear end faces of the upper and lower wings of the slider, so that the slider cannot be moved further with part of the bottom stopper portion engaging the element guide groove of the slider.
Still further, according to the present invention, preferably, the material of the bottom stopper portion is composed of a laminated film piece having two or more layers while at least material of the bottommost layer has adhesiveness with respect to the composition fibers of the fastener tape, or alternatively at least the material of the topmost layer of the laminated film piece having two or more layers is composed of a material having a higher melting point than the other layers.
The material to be used for the bottom stopper portion may be different from the material to be used for the fastener tape. For example, a modified polyester film having a lower melting point is employed for the bottom stopper portion while nylon having a higher melting point than the modified polyester film is employed for the composition yarns of the fastener tape. However, the polyester resin and nylon resin have low adhesive property. Thus even if the modified polyester resin is fused to the nylon resin, it may be separated because its adhesion is weak.
Thus, the present invention is preferable especially in the case that the bottom stopper portion and the fastener tape are composed of different materials, particularly their adhesion are weak. According to the present invention, the material having excellent adhesive property with respect to the composition yarns of the fastener tape is used for at least the bottommost layer of the material of the bottom stopper portion to be fused. Further, in the present invention, it is preferable that the bottom stopper portion and the fastener tape are composed of the same material, which is most preferable when only the bottom stopper portion is fused to the composition yarns of the fastener tape without melting the composition yarns.
Still further, according to the present invention, it is preferable that the side of the fastener element row on the inner side of the fastener tape is disposed in said rough-pattern-structure region.